Implement plugin dependencies, loaded in dependency first order (#1701)

* Implement plugin dependencies, loaded in dependency first order

# Conflicts:
#	chunky/src/java/se/llbit/chunky/main/Chunky.java

* Add additional documentation

* Move plugin loader api out into a separate class.

This also makes PluginManager much easier to test.

* Add tests to verify load order of plugins with dependencies.

* Apply review suggestions

* Add maven-artifact:3.9.9 dependency.

---------

Co-authored-by: Maik Marschner <[email protected]>

README.md

@@ -200,6 +200,9 @@ Chunky uses the following 3rd party libraries:
   The library is covered by the Apache License, version 2.0.
   See the file `licenses/Apache-2.0.txt` for the full license text.
   See the file `licenses/commons-math.txt` for the copyright notices.
+- **Apache Maven Artifact by the Apache Software Foundation**  
+  The library is covered by the Apache License, version 2.0.
+  See the file `licenses/Apache-2.0.txt` for the full license text.
 - **FastUtil by Sebastiano Vigna**  
   FastUtil is covered by Apache License, version 2.0.
   See the file `licenses/Apache-2.0.txt` for the full license text.

chunky/build.gradle

@@ -17,6 +17,7 @@ dependencies {
   implementation 'org.apache.commons:commons-math3:3.2'
   implementation 'com.google.code.gson:gson:2.9.0'
   implementation 'org.lz4:lz4-java:1.8.0'
+  implementation 'org.apache.maven:maven-artifact:3.9.9'
   implementation project(':lib')
 }
 

chunky/src/java/se/llbit/chunky/main/Chunky.java

@@ -23,10 +23,10 @@
 import se.llbit.chunky.block.MinecraftBlockProvider;
 import se.llbit.chunky.block.legacy.LegacyMinecraftBlockProvider;
 import se.llbit.chunky.main.CommandLineOptions.Mode;
-import se.llbit.chunky.plugin.ContextMenuTransformer;
-import se.llbit.chunky.plugin.PluginApi;
-import se.llbit.chunky.plugin.ChunkyPlugin;
-import se.llbit.chunky.plugin.TabTransformer;
+import se.llbit.chunky.plugin.*;
+import se.llbit.chunky.plugin.loader.PluginManager;
+import se.llbit.chunky.plugin.loader.JarPluginLoader;
+import se.llbit.chunky.plugin.manifest.PluginManifest;
 import se.llbit.chunky.renderer.*;
 import se.llbit.chunky.renderer.RenderManager;
 import se.llbit.chunky.renderer.export.PictureExportFormat;
@@ -43,7 +43,6 @@
 import se.llbit.chunky.ui.render.RenderControlsTabTransformer;
 import se.llbit.chunky.world.MaterialStore;
 import se.llbit.json.JsonArray;
-import se.llbit.json.JsonValue;
 import se.llbit.log.ConsoleReceiver;
 import se.llbit.log.Level;
 import se.llbit.log.Log;
@@ -55,11 +54,10 @@
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
+import java.util.*;
 import java.util.concurrent.ForkJoinPool;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Chunky is a Minecraft mapping and rendering tool created byJesper Öqvist ([email protected]).
@@ -265,35 +263,31 @@ private void loadPlugins() {
     }
     Path pluginsPath = pluginsDirectory.toPath();
     JsonArray plugins = PersistentSettings.getPlugins();
-    Set<String> loadedPlugins = new HashSet<>();
-    for (JsonValue value : plugins) {
-      String jarName = value.asString("");
-      if (!jarName.isEmpty()) {
-        Log.info("Loading plugin: " + value);
-        try {
-          ChunkyPlugin
-              .load(pluginsPath.resolve(jarName).toRealPath().toFile(), (plugin, manifest) -> {
-                CreditsController.addPlugin(manifest);
-                String pluginName = manifest.get("name").asString("");
-                if (loadedPlugins.contains(pluginName)) {
-                  Log.warnf(
-                      "Multiple plugins with the same name (\"%s\") are enabled. Loading multiple versions of the same plugin can lead to strange behavior.",
-                      pluginName);
-                }
-                loadedPlugins.add(pluginName);
-                try {
-                  plugin.attach(this);
-                } catch (Throwable t) {
-                  Log.error("Plugin " + jarName + " failed to load.", t);
-                }
-                Log.infof("Plugin loaded: %s %s", manifest.get("name").asString(""),
-                    manifest.get("version").asString(""));
-              });
-        } catch (Throwable t) {
-          Log.error("Plugin " + jarName + " failed to load.", t);
-        }
+    // TODO: allow plugins to implement a custom plugin loader.
+    PluginManager pluginManager = new PluginManager(new JarPluginLoader());
+
+    // Parse plugin manifests
+    Set<PluginManifest> pluginManifests = plugins.elements.stream()
+      .map(value -> value.asString(""))
+      .filter(jarName -> !jarName.isEmpty())
+      .map(jarName -> pluginsPath.resolve(jarName).toAbsolutePath().toFile())
+      .map(PluginManager::parsePluginManifest)
+      .flatMap(Optional::stream)
+      .collect(Collectors.toSet());
+
+    // Load plugins
+    pluginManager.load(pluginManifests, (plugin, manifest) -> {
+      String jarName = manifest.pluginJar.getName();
+      Log.infof("Loading plugin: %s", jarName);
+      CreditsController.addPlugin(manifest.name, manifest.version.toString(), manifest.author, manifest.description);
+
+      try {
+        plugin.attach(this);
+      } catch (Throwable t) {
+        Log.error("Plugin " + jarName + " failed to load.", t);
       }
-    }
+      Log.infof("Plugin loaded: %s %s", manifest.name, manifest.version);
+    });
   }
 
   /**

chunky/src/java/se/llbit/chunky/plugin/loader/JarPluginLoader.java

@@ -0,0 +1,45 @@
+package se.llbit.chunky.plugin.loader;
+
+import se.llbit.chunky.Plugin;
+import se.llbit.chunky.plugin.PluginApi;
+import se.llbit.chunky.plugin.manifest.PluginManifest;
+import se.llbit.log.Log;
+
+import java.io.File;
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.function.BiConsumer;
+
+@PluginApi
+public class JarPluginLoader implements PluginLoader {
+  public void load(BiConsumer<Plugin, PluginManifest> onLoad, PluginManifest pluginManifest) {
+    try {
+      Class<?> pluginClass = loadPluginClass(pluginManifest.main, pluginManifest.pluginJar);
+      Plugin plugin = (Plugin) pluginClass.getDeclaredConstructor().newInstance();
+      onLoad.accept(plugin, pluginManifest);
+    } catch (IOException | ClassNotFoundException e) {
+      Log.error("Could not load the plugin", e);
+    } catch (ClassCastException e) {
+      Log.error("Plugin main class has wrong type (must implement se.llbit.chunky.Plugin)", e);
+    } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
+      Log.error("Could not create plugin instance", e);
+    }
+  }
+
+  /**
+   * This method is {@link PluginApi} to allow plugins to override only classloading functionality of the default plugin loader.
+   *
+   * @param pluginMainClass The plugin's main class to load.
+   * @param pluginJarFile The jar file to load classes from.
+   * @return The loaded plugin's main class
+   * @throws ClassNotFoundException If the main class doesn't exist
+   * @throws MalformedURLException If the jar file cannot be converted to a URL
+   */
+  @PluginApi
+  protected Class<?> loadPluginClass(String pluginMainClass, File pluginJarFile) throws ClassNotFoundException, MalformedURLException {
+    return new URLClassLoader(new URL[] { pluginJarFile.toURI().toURL() }).loadClass(pluginMainClass);
+  }
+}

chunky/src/java/se/llbit/chunky/plugin/loader/PluginLoader.java

@@ -0,0 +1,18 @@
+package se.llbit.chunky.plugin.loader;
+
+import se.llbit.chunky.Plugin;
+import se.llbit.chunky.plugin.PluginApi;
+import se.llbit.chunky.plugin.manifest.PluginManifest;
+
+import java.util.function.BiConsumer;
+
+@PluginApi
+public interface PluginLoader {
+  /**
+   * Load the plugin specified in the manifest
+   * @param onLoad The consumer to call with the loaded plugin
+   * @param pluginManifest The plugin to load.
+   */
+  @PluginApi
+  void load(BiConsumer<Plugin, PluginManifest> onLoad, PluginManifest pluginManifest);
+}